what is the ratio of F plasmids that cross the pillus into the new cell?

10 x -6....aka, one in a million.

what is the first step of CONjuGATION involving an Hfr cell?

The F plamid integrates into chromosome by recombination

what does HfR stand for?

High frequency of Recombination

How is an Hfr cell created?

when an F+ cell integrates its F plamid into its chromosome. Hfr cells donate a partial copy of their DNA and a portion of the F plasmid to a recipient, which is rendered a recombinant cell but remains F-.